1. KS3 D&T Lesson Plastic products and manufacturing

2. Plastics are everywhere!
Where have you
found them today? 2

3. What are plastics are made from?
Natural materials like cellulose, coal,
crude oil, natural gas and salt.
Plastics can also be made from renewable
sources like corn, potatoes and sugar cane. 3

4. Plastics are Polymers 4 Polymers are very long molecules,
made by joining many ‘building block’
molecules into a chain
Different ‘building blocks’ create different chains – with different properties
Polymers come in two forms,
thermoplastics and thermosets 4

5. Thermoplastics 5 Thermoplastics soften when heated.
All thermoplastics can be melted and reshaped many times. 5

6. Thermosets
During moulding, thermoset molecules form a tightly woven 3D network.
This means thermosets cannot be re-melted and changed in shape. 6

7. Types of Plastics 7 There are several hundred different
Each has properties
that make it suitable
for specific uses. 7

8. High-Density Polyethylene HDPE
For containers, toys, utensils, industrial wrapping film and gas pipes. 8

9. PET
For bottles, textile fibres and film food packaging. 9

10. Polypropylene (PP)
For transparent all-weather sheeting, electrical insulators, bathroom units and automotive parts. 10

11. Polystyrene – PS 11 For electrical appliances, insulation,
cups and plates, and toys. 11

12. PVC
For window frames, pipes, flooring, wallpaper, bottles, cling film, toys, guttering, cable insulation, credit cards, and medical products. 12

13. Low-Density Polyethylene (LDPE)
For pallets, agricultural films, bags, toys, coatings, containers, pipes, wrappings. 13

14. ABS
For general
appliance mouldings. 14

15. How are Plastics formed?15

16. Injection Blow Moulding
Plastic granules are heated and then extruded into the first mould. This creates the ‘pre form’: a completed neck with a tube of thick plastic attached. This is moved into a second mould and air injected to ‘blow’ it into the shape of the final mould, to form the product.
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17. Extrusion Blow Moulding
Plastic granules are heated and then extruded into a mould. When the plastic is the right length in the mould it is cut off and air injected to ‘blow’ it into the shape of the mould, to form the product.
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18. Extrusion
Plastic granules are melted then injected at high pressure through a ‘die’ to make a continuous length of plastic with a constant cross section. This cross section is called the profile.
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19. Injection Moulding 19 Plastic granules are melted then injected
at high pressure into a
hot mould to form
the product.
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20. Thermoforming
Plastic sheet is heated and formed using a press and / or vacuum to form the product.
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21. Rotational Moulding
Plastic granules are added to a heated mould which is then rotated to coat the inside and form a thick-walled, strong product.
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22. ANSWERS 22 Builder Beams – Extrusion Bump’ems – Rotational moulding
Easy Trays – Thermoforming
Crystal Cashmere – Injection Blow Moulding
One spoon at a time – Extrusion Blow Moulding
Flatpack Friends – Injection Moulding 22